Abstract: A collection made in October showed two well developed mi-crosporangia, borne on the ventral surface of each microsporophyll. A mass sporogenous cells wwere dividing within the microsporangium. In the following spring, at end of January to early February, the microspore mother cells were beginning for reduction division. During the reduction division period, the distribution of starch grains change. The formation of tetrads at the early February, and tapetal were gradually disintegrated. The formation of uninu- cleate pollen grain at the middle of February. The pollen grain soon develops two extensions of the exine whlich form the two wings. lt is heteroplar and radiosymtnetric. The pollen in shed at the four-celled stage in March.

Key words: P. yunnanensis

摘要： 云南松（Pinus，yunnanensis Fr.）雄配于体于10月在小孢子叶腹面产生二个小孢子囊，内有许多进行分裂的造孢组织细胞。第二年一月下旬至二月初小孢子母细胞进行减数分裂。在分裂期间，细胞内所贮存的淀粉粒的分布发生变化。二月初四分体小抱于形成，绒毡层细胞解体。二日中旬单核花粉粒形成，外壁扩展形成二个异极对称的气囊。三月花粉在四细胞时期散发。

关键词: 云南松, 雌雄配子体